Composition containing olefinically unsaturated compounds and hydrazones

ABSTRACT

Compositions containing a radical-polymerizable olefinically unsaturated compound and a hydrazone of an aromatic aldehyde or ketone are provided. Also provided are methods for the production of such compositions and methods for the use of such compositions as an adhesive and sealing compound or its use for the coating and production of plastic moldings. The compositions polymerize radically at room temperature upon exposure to ambient air.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a composition containing aradical-polymerizable olefinically unsaturated compound and a hydrazoneof an aromatic aldehyde or ketone. The invention also relates to itsproduction and to its use as an adhesive and sealing compound and to itsuse for the coating and production of plastic moldings. The compositionsaccording to the invention polymerize radically at room temperature.

2. Discussion of Related Art

For curing by peroxides or hydroperoxides, olefinically unsaturatedsystems require selected initiators or activator systems particularlywhen the reaction is to be initiated at low temperatures, for example atroom temperature or only slightly elevated temperatures. For example, itis known that selected tertiary amine compounds with partial aromaticsubstitution at the N atom perform such an activating function. Knownactivators for initiating polymerization, for example with dibenzoylperoxide, are in particular dimethyl aniline and dimethyl-p-toluidine.

A totally different known class of activators for oxidatively initiatingthe polymerization of certain unsaturated systems, namely drying oils,are metal compounds--at least partly soluble in the system--of metalswhich can occur in several valency stages and which accelerate theinitiation reaction via intermediately occurring valency shifts oninteraction with other components of the system. Metal compounds of suchmetals which are adequately soluble in organic solvents and/or inbinders have long been known as so-called drying agents for the airdrying of paints, varnishes and the like based on unsaturated oils.Sufficiently oil-soluble compounds of transition metals which arecapable of occurring in several valency stages are particularly suitablefor this purpose. The individual components differ considerably in theirability to accelerate hardening. Compounds of cobalt and/or manganeseare particularly suitable, although iron also has an accelerating effecton curing. In addition, comparable compounds of other metals, which arealso capable of developing several valency stages, may be used,particularly in combination with these highly effective metalliccomponents. A detailed description of such systems can be found, forexample, in "Ullmann, Encyklopadie der technischen Chemie", 4th Edition,Vol. 23 (1983), 421 to 424.

U.S. Pat. Nos. 4,010,152 and 4,063,012 describe the (co)polymerizationof ethylenically unsaturated monomers, such as vinyl chloride, withselected aliphatic alphahydroperoxy)-azo compounds or salts thereofwhich, on the basis of the structural formulae provided, may be assignedto the class of hydrazone derivatives and which may be regarded asselected hydrazone peroxides. According to the teaching of the first ofthese two documents, they are prepared by reaction of alpha-halo-azocompounds with sodium peroxide or hydrogen peroxide in the presence ofacid acceptors and are said then to be used to initiate polymerization.The majority of the Examples of this document and the parallel secondU.S. patent cited above describe the production of the hydroperoxidecompounds by a method which is not explained in detail in the generaldescription of the invention. The particular hydrazone compoundsselected are dissolved in a solvent and aerated with a stream of oxygenby passing the oxygen through the solution of hydrazone compounds keptat room temperature or at slightly elevated temperatures. The particularhydroperoxides are obtained in yields of 80% or more and are optionallypurified by low-temperature crystallization. The hydroperoxides may beused as initiator systems for the polymerization of, for example, vinylchloride or unsaturated polyester/styrene resins.

A number of earlier publications is concerned with compounds of thistype and with their formation, in particular by autoxidation. In 1914,M. Busch et al. described the autoxidation of hydrazones in Ber. 47(1914), 3277 to 3291. The alleged formation of the peroxides isformulated here as the addition of an oxygen molecule onto the C:Ndouble bond of the hydrazone to form a four-membered peroxide ring. Theautoxidation of phenyl hydrazones is also described in K. H. Pausacker,J. Chem. Soc. 1950, 3478 to 3481. This Article discusses thenon-catalyzed reaction of pure phenyl hydrazines and the correspondingreactions with addition of a small quantity of benzoyl peroxide as acatalyzed reaction. A more detailed structural elucidation of theconstitution of hydrazone peroxides is provided by R. Criegee et al. inBer. 84 (1951), 219 to 224 where it is shown that the hydrazoneperoxides can only be formed from derivatives of hydrazine compoundswhich still contain a hydrogen atom at the substituted N atom, at leastat room temperature or correspondingly low temperatures.

U.S. Pat No. 4,855,373 describes trifunctional hydrazones, namelyaliphatic and aromatic hydrazones of 1,3,5-tris-acetyl benzene, as aninitiator for the polymerization of vinyl compounds. Acrylic acid andacrylic acid amides and esters with C₁₋₄ alcohols are preferablypolymerized with 1,3,5-tris-(acetyl-t-butylhydrazonyl)-benzene. Thepolymerization takes place in the presence or absence of atmosphericoxygen, its removal being preferred. The acrylic acid, of which theaqueous solution has been purged with nitrogen, polymerizes in 30seconds on addition of a hydrazone solution (see Example 1). If thesolution is not purged with nitrogen, no polymerization takes place for2 minutes, but presumably does proceed in the event of subsequentpurging with nitrogen. Accordingly, polymerization begins immediatelyafter the vinyl monomers and the hydrazone compounds have been mixed.

Earlier patent application DE 40 00 776 describes hydrazone compoundscorresponding to the following general formula as an initiator or as theprinciple component of an initiator system for curing olefinicallyunsaturated compounds by radical polymerization with ambient air:##STR1## in this formula, R₁, R₂ and R₃ are at least partly the same ordifferent and have the following meanings:

R₁ is a linear, branched or cyclic and optionally substituted alkylradical or an optionally substituted aryl radical,

R₂ is hydrogen, a linear, branched or cyclic and optionally substitutedalkyl radical or an optionally substituted aryl radical;

R₁ and R₂ together with the co-substituted carbon atom may also form acycloaliphatic radical which may even be substituted,

R₃ is a linear, branched or cyclic and optionally substituted alkylradical or an optionally substituted aryl radical.

DESCRIPTION OF THE INVENTION

The problem addressed by the invention was to use the establishedknowledge described above to develop new possibilities for the practicaluse of initiators or activators and activator systems which could beused in a simplified manner to initiate the polymerization ofolefinically unsaturated systems. In admixture withradical-polymerizable compounds or mixtures, the activators would becapable of activation by exposure to ambient air. In preferredembodiments, the activators would be activated at temperatures as low asroom temperature, although they could also be activated at slightlyelevated temperature. One particularly important aspect of the inventionis concerned with multicomponent systems of the type mentioned which arecapable of initiating the start of a radical polymerization ofunsaturated systems simply by exposure to ambient air at roomtemperature--with timed curing and a predetermined pot life. In oneimportant embodiment, the invention seeks in particular to provideone-component storable systems which are plastic, more particularlypaste-like to fluid, in the form in which they are applied and whichhave a sufficient pot life for processing, but which subsequently curein dimensionally stable form simply by exposure to ambient air.

The solution provided by the invention is characterized in the claims.It is based on a knowledge of the measures with which the polymerizationof the composition can be controlled in such a way that, on the onehand, the composition can be stored at room temperature and, on theother hand, it can readily be polymerized at any desired time. This isbecause, in the substantial absence of radical-forming agents, such asoxygen, peroxides, hydroperoxides, etc., the composition is stable instorage, i.e. no polymerization takes place for at least 2 months andpreferably for at least 12 months at room temperature, as reflected inthe virtually unchanged viscosity. The composition is at least stilluseable for the particular application envisaged. However,polymerization is initiated by simple exposure to air at ambienttemperature or elevated temperature and is completed in an acceptabletime. Accordingly, one-component adhesives, sealing compounds, coatingcompounds and molding compounds can be produced and stored withvirtually no loss of activity. The open time of the system required forprocessing by forming may largely be freely selected. Accordingly, thecompositions according to the invention are of considerable practicalsignificance in many fields of application.

Accordingly, the present invention relates to a storable compositioncontaining a radical-polymerizable olefinically unsaturated compound anda hydrazone corresponding to the following general formula ##STR2## inwhich n is a number of 1 to 3,

R₁ is hydrogen or an alkyl group containing up to 40 carbon atoms and

R₂ independently of the other substituents is hydrogen or an aromatic oraliphatic group containing up to 40 carbon atoms.

The "olefinically unsaturated compounds" include any acyclic and cyclicaliphatic hydrocarbons containing one or more reactive double bonds inthe molecule. More particularly, they include any vinyl monomers and, inaddition, acrylic acid, methacrylic acid, styrene and butadiene andderivatives thereof. They may also be completely or partly present inthe form of reactive preformed oligomer and/or polymer compounds.Monomers or oligomers containing free carboxylic acid groups areparticularly preferred.

The hydrazone compounds according to the invention are monofunctional,difunctional and trifunctional. The trifunctional compounds arepreferred. The substituents R₁ and R₂ are preferably linear and/orcyclic alkyl groups containing up to 40 carbon atoms and, moreparticularly, 3 to 8 carbon atoms. At least one substituent R₂ permolecule should be such an alkyl group. The substituents R₁ and R₂ maybe unsubstituted or substituted. It is important in this regard to bearin mind the fact that, by the substitution of these radicals, moreparticularly the radical R₂, a certain influence can be exerted on thereactivity of the activator system. If, for example, an aromatic system,more particularly a phenyl radical, is present, suitable substitution ofthis phenyl radical enables the reaction to be accelerated by theprovision of electron-shifting substituents known per se at this phenylradical in R₂. The relevant prior art cited above provides clearreferences to this effect, see for example the literature referencePausacker loc. cit., page 3480, Table. Electron-shifting and hencereaction-accelerating substituents are, for example., alkyl, alkoxyand/or halogen substituents at the phenyl radical in R₂. Conversely,strongly electron-attracting substituents of the NO₂ group type have adecelerating effect on the reaction. Electron-shifting andelectron-attracting effects such as these by substitution and thestructure of the particular substituents are general knowledge amongexperts.

The substituent R₁ in the general formula can also influence thevelocity of the reaction through the choice of the particularconstitution and any substitution envisaged. The relevant literaturecited in the foregoing is again worth consulting in this regard, cf. thecited Article by Criegee et al. loc. cit., page 222, and the literaturecited in connection with the Table.

The above-cited U.S. Pat. No. 4,010,152 with its formula diagrams incolumns 6 to 14 provides an insight into the extraordinarymany-sidedness of the special character of the substituents R₁ and R₂ inthe compounds corresponding to the general formula. The hydrazonecompounds are shown in the form of their hydroperoxides which are alsoformed in accordance with the invention on exposure to air where thereaction is carried out in situ. The detailed particulars provided inthe document in question on the particular character of the hydrazonecompounds or rather the hydroperoxides formed in situ therefrom apply tothe teaching according to the invention in connection with thedefinition of the compounds corresponding to the general formula. Forreasons of expediency, reference is made to this detailed printeddescription in connection with the disclosure of the present invention.The benzene ring may of course contain other substituents providing theydo not affect the starting function. Specific examples are acetophenonemethyl hydrazone (n=1, R₁ =R₂ =CH₃), acetophenone-t-butyl hydrazone(n=1, R₁ =CH₃, R₂ =C(CH₃)₃).

The preferred hydrazone is 1,3,5-tris-(acetylalkylhydrazone)-benzene.

As already mentioned, particular importance is attributed to thesignificance of the composition for the intended polymerization,particularly in regard to storage. According to the invention, theoxygen can be removed by degassing. To this end, the homogenizedcomposition is preferably exposed to a vacuum of 0.5 torr for 2 to 5minutes at approximately -196° C. without the hydrazone and is thenheated to room temperature. Residual oxygen is removed from the systemby multiple repetition of this freezing/thawing cycle. A simple andsimulated practical method is to store the composition at 80° C. in theabsence: of air. After 24 hours, no polymerization should have occurred.Degassing may also be carried out by other methods, for exampleultrasonically or chemically.

It is known that olefins and other unsaturated compounds, moreparticularly polymerizable monomers, have to be stabilized for storage.The following basic reactions are used for this purpose:

1. stabilization against oxygen by addition of antioxidants and

2. stabilization against radicals by addition of radical inhibitors.

From general chemical knowledge, typical stabilizer components arelisted in the following, the mechanism to which the stabilizer is to beassigned being indicated in brackets after the particular compound:pyrogallol (1), O₂ -inhibited acrylates (1), hydroquinone (1,2),hydroquinone monomethyl ether (1,2), butyl hydroxytoluene (2) andphenothiazine (2). Deoxidizers of the triphenyl phosphine type andiodide/iodine solutions are of particular importance for stabilizing thesystem against unwanted premature reaction. The quantity in which theyare used is adapted to the particular application involved. It mayreadily be determined in individual cases by relevant considerationsand/or by preliminary tests. Quite generally, the percentage by weightof stabilizers is at most 5% by weight and preferably from 0.01 to 1% byweight, based on the composition as a whole. An excessive quantityretards the desired polymerization on exposure to air.

The composition according to the invention also preferably contains anaddition of metal compounds which can occur in several valency stages.Selected representatives of the transition metals can be particularlyactive in this regard. The particular choice of the metal can determineinter alia the rate at which the polymerization reaction is initiated.Components highly active at room temperature are derived, for example,from copper, cobalt, vanadium and/or manganese. However, particularsignificance is attributed to compounds of iron which have a goodaccelerating effect on the reaction. Iron, cobalt and/or manganesecompounds are particularly suitable for use at room temperature, whichis of particular advantage for many applications, optionally being usedin admixture with other metallic components, such as compounds of lead,cerium, calcium, barium, zinc and/or zirconium. The relevant specialistliterature may be consulted in this regard, cf. for example the citedpublication in "Ullmann" loc. cit. and the literature cited therein. Themetals in question are used in the form of such as compounds that theyare at least partly soluble in the system as a whole. Both soap-likemetal compounds and other types otherwise bonded to organic radicals,particularly in complex form, are suitable. A typical example of theprocedure adopted in accordance with the invention is the use ofcorresponding metal naphthenates or metal acetyl acetonates. If,however, inorganic salts are sufficiently soluble in the system, it isalso possible to use such inorganic systems. A typical example of thisis iron chloride which has a distinct accelerating effect when used inthe system according to the invention. It may be advisable to use themetal compounds in a low valency stage of the metal, i.e. for example ascobalt (II) or manganese (II). In other cases, the metal compound may beused in a higher valency stage of the metal. For example, iron may alsobe used in the form of Fe³⁺ compounds.

The activator components of the type in question, which are optionallyused in accordance with the invention, are the various mixturecomponents with a reducing effect which are used in typical redoxsystems for initiating polymerization reactions. Reference is made inthis regard to the extensive relevant literature, for example W. Kern,Makromol. Chem. 1, 249 (1947) and C. Srna, Angew. makromol Chem. 9, 165(1969), and also to general specialist knowledge as described, forexample, in Houben-Weyl "Methoden der organischen Chemic", Vol. 14/1,263 to 297. The class of alpha-hydroxyketones as represented, forexample, by butyroin, benzoin of acetoin has proved to be particularlyactive in this regard. However, the teaching according to the inventionis by no means limited to this particular class. Reference is made tothe modifications illustrated in the Examples according to theinvention. What is crucial is that, although this class of compounds iscapable of performing an important reaction-accelerating function in theactivator systems used in accordance with the invention, their use isnot compulsory.

Initiators or activator systems from the principal components describedin the foregoing, namely hydrazone compound, at least partly solublemetallic drying agent and/or any accelerator used, are all capable afteradsorbing ambient air of initiating the radical-polymerizableolefinically unsaturated systems which, hitherto, have been used withvarious and, in particular peroxidic, initiator systems.

Definitions of the other constituents of the composition according tothe invention can be found in the relevant literature concerned with theproduction and processing of systems based on olefinically unsaturated,radical-polymerizable compounds. An extremely large number of systems ofthis type tailored in their properties to suit the particularapplication are now available among experts. Olefinically unsaturatedreactive systems can be built up on the basis of selectedradical-polymerizable ethylenically unsaturated compounds or on thebasis of mixtures of several types of such compounds. The ethylenicallyunsaturated polymerizable components may be monofunctional compoundsand/or polyfunctional reactive components.

The polymerization reaction can actually be carried out withnon-thickened composition, i.e. for example with the pure monomermixture. In that case, the viscosity is in the range from about 1 to 5mPa.s. However, the composition selected should preferably have aninitial viscosity of at least about 30 to 100 mPa.s and preferably of atleast about 200 or 300 mPa.s. Particularly safe initiation of thepolymerization reaction can be expected in the case of systems having aninitial viscosity of at least about 500 mPa.s and, more particularly, ofat least about 1,000 mPa.s. All these viscosity values are determined asBrookfield viscosities. Commercially available adhesive systems areknown to have viscosities of at least about 3,000 mPa.s and, moreparticularly, up to about 10,000 mPa.s. Materials of this type are ofcourse eminently suitable for processing in accordance With theinvention. However, the invention is by no means limited to suchmaterials. Systems of much lower viscosity, for example spreadablelacquer systems, which are used in particular as solventless systems,are also suitable for the reaction-initiating mechanism described hereinproviding the material to be processed by forming has the minimuminitial viscosity values mentioned above. The same also applies to otherapplications, for example the production of plastic moldings based onstyrene/unsaturated polyester resins. The necessary initial viscosityvalues can be adjusted in particular by mixtures having an adequatecontent of oligomeric and/or polymeric components, optionally inadmixture with low molecular weight, unsaturated components liquid atroom temperature, such as (meth)acrylates. However, correspondingly,viscous compositions can also consist solely of precondensates ofsuitable fluidity. The extensive knowledge of experts on suchethylenically unsaturated mixtures curable by radical polymerization isapplicable in this regard.

The multicomponent mixtures to be used in accordance with the inventionare generally formulated as onecomponent systems which are protectedagainst contact with air pending their use. However, they may also beformulated as multicomponent systems, in which case the components aremixed together for the practical application of the system. The open potlife of the system can be regulated by suitably selecting and adaptingthe principal components of the activator system, so that in this case,too, the start of the initiation reaction and, ultimately, the curing ofthe system can take place in air under ambient conditions. In oneembodiment of the invention, the multicomponent mixtures in question ofthe activator system and polymerizable components are present astwo-component systems which do not react even on contact with air. Inthis case, it is particularly preferred to separate the main componentsof the activator systems used in accordance with the invention from oneanother in such a way that the hydrazone compound is kept separate fromthe metal compounds. Both components may thus generally containethylenically unsaturated reactive mixture. For processing, the twoseparately stored components merely have to be mixed, processed byforming during the open pot life of the system and finally exposed toair.

The invention provides for the formulation of optimized mixtures.Without in any way departing from the scope of the invention, solubleand/or insoluble fillers, elasticizing agents, thickeners,thixotropicizing agents, pigments, coupling agents and the like may beused with no adverse affect on the performance of the initiator systemaccording to the invention. This does of course presuppose that anyproblems in the interaction of the starter components are safely ruledout by suitably selecting the auxiliaries and fillers. General chemicalknowledge may be applied to this end.

In the multicomponent mixtures according to the invention, the startermixtures preferably make up no more than about 15% by weight and, inparticular, no more than about 10% by weight, based on the weight of thesystem as a whole. Depending on the activity of the components used, theweight of the starter mixture can be reduced very considerably, forexample to around 0.1% by weight or to at least about 0.5% by weight.Quantities of the starter system of at least about 1% by weight areparticularly preferred, quantities of up to about 8% by weight beingespecially suitable. All these figures are based on the one hand on thetotal weight of the composition according to the invention and on thetotal weight of the three main components of the starter system.

The three above-mentioned components of the starter system mayadvantageously be used in the following quantities (in % by weight,based on the system as a whole):

hydrazone compounds: at least about 0.1% by weight, preferably 0.5 to7.5% by weight and more preferably 1 to 4% by weight

soluble metal compound: 0 to 5% by weight, preferably 0,005 to 1% byweight and more preferably 0.1 to 5% by weight

deoxidizer: 0 to 5% by weight and preferably 0.01 to 1% by weight.

Mixtures of oligomers and/or polymers together with ethylenicallyunsaturated monomers of low molecular weight are used as the mixtures ofradical-polymerizable compositions suitable for a wide variety ofpractical applications. The relatively high molecular weight componentsof the mixtures are often at least partly soluble in the monomers.Mixtures of this type are particularly suitable for processing inaccordance with the invention. The content of monomers, for example ofthe (meth)acrylate, optionally substituted styrene and/or acrylonitriletype, is generally at least 10% by weight and preferably at least about20% by weight and in many cases, may even be at least about 40% byweight (based on the reactive mixture as a whole). The monomer componentmay be by far the predominant component in terms of weight, so that forexample 60 to 80% by weight of the mixture as a whole can be made up bythe low molecular weight monomer. As previously explained, however, itis important to bear in mind the fact that the use of an adequatequantity of compounds of relatively high molecular weight and/or otherthickening agents guarantees the at least slightly increased initialviscosity of the mixtures for safely initiating the reaction on exposureto air.

In characteristic examples of application, which fall within the scopeof the invention as preferred embodiments, these conditions of use areguaranteed in any event. Without any claim to completeness, thefollowing examples are mentioned here: aerobically curing sealing andadhesive systems, spreadable compositions for surface coating withpolymerizable, more particularly solventless lacquers and paints in theform of spreadable air-drying lacquer systems and the production ofmolded articles with initiation of the reaction by exposure to ambientair, for example based on styrene/unsaturated polyester resins.

EXAMPLES

For the following Examples, the ethylenically unsaturated compounds(also referred to hereinafter as monomers) are freed from any inhibitorspresent and, where possible, purified by distillation. In the case oflow-volatility, non-distillable monomers, dissolved oxygen was removedby evacuation and subsequent purging with nitrogen for several hours.The monomers were stored in an inert gas (nitrogen or argon) andremoved.

The hydrazones were prepared by methods known from the literature (see,for example, Houben-Weyl, "Methoden der organischen Chemie", Vol. X/2),stored in a an inert gas and removed.

To determine the cure time of the polymerizable multicomponent mixtures,100 mg of the mixture formulated in an inert gas atmosphere was exposedto ambient air in a watchglass. The mixture is regarded as cured whenthe total quantity of sample has changed into a thermoplastic orthermoset solid.

For bonding, test specimens corresponding to DIN 53 281 are providedwith the polymerizable mixture and, before fitting together, are exposedto the ambient air for a certain period (90 to 600 seconds).

The tensile shear tests are carried out in accordance with DIN 53283 onsingle overlap (250 mm²) specimens.

To determine the storage time, approx. 7 g of the composition wereintroduced by syringe in the absence of oxygen into commerciallyavailable argon-filled adhesive tubes of an A1 alloy approximately 1 cmin diameter and approximately 8 cm in length. The tubes were closed bymeans of a tube clamp and stored at the temperatures indicated. Fromtime to time, the viscosity was visually examined for any significantchange. If this is not the case, the composition is regarded as stablein storage.

The following general procedure was used for the Examples:

The monomer was initially introduced into a nitro-gen-filledmultiple-necked flask and the thickener subsequently dissolved thereinor a mixture was used from the outset. The metal compound, theactivator, the inhibiting stabilizer and a coupling agent were thenadded, again in the absence of oxygen. The homogenized mixture wascooled to -196° C. and the flask was evacuated to 0.5 torr andsubsequently heated to room temperature. Residual oxygen was removedfrom the system by multiple repetition of this freezing/thawing cycle.The hydrazone compound was then added and the mixture was degassed asdescribed above and stored in an inert gas atmosphere.

Production Example a: Acetophenone methyl hydrazone

The reaction was carried out in the strict absence of oxygen in an inertgas (nitrogen) atmosphere. 27.5 g methyl hydrazine were added dropwiseto 75 g acetophenone over a period of 5 minutes, after which thereaction mixture was heated for 6 h to 60° C. 30 g Na₂ SO₄ were thenadded and the solid was filtered off at room temperature. The solutionwas then subjected to fractional distillation. Boiling point: 90 to 92°C. (0.8 mbar). Yield 59 g (65%).

Production Example b: Acetophenone t-butyl hydrazone

The reaction was carried out in the strict absence of oxygen in an inertgas (nitrogen) atmosphere. 17.5 g acetophenone, 18.7 g t-butyl hydrazinehydrochloride, 12 g 50% NaOH and 60 ml ethanol were heated for 14 hoursto the reflux temperature. 70 ml diethyl ether and 60 ml water wereadded to the reaction mixture and, after vigorous stirring, the organicphase was removed and washed with 50 ml water. After drying with Na₂SO₄, the ether was removed in a rotary evaporator and the residue wassubjected to fraction distillation. Boiling point: 86° to 89° C. (2mbar). Yield: 24 g (83%).

The compositions consisted of the following components and were degassedas follows:

    ______________________________________                                                  Exam- Exam-   Exam-   Compar-                                                                              Exam-                                            ple   ple     ple     ison   ple                                              1     2       3       I      4                                      ______________________________________                                        1.  Compon-                                                                       ents                                                                          GM 9     .sup.a) g                                                                            20    20    20    --     20                                   GM 1     .sup.b) g                                                                            --    --    --    10     --                                   Fe       .sup.c) g                                                                            2.6   --    2.6   --     2.6                                  (acac).sub.3                                                                  BUTY-    .sup.d) g                                                                            0.4   --    0.4   --     --                                   ROIN                                                                          Iodine   .sup.e) ml                                                                           0.5   0.5   0.5   --     0.75                                 solution                                                                      JPA-514  .sup.f) g                                                                            0.1   0.1   --    --     0.1                                  Meth-    .sup.g) g                                                                            --    --     1    --     --                                   acryloyl                                                                      hydroxy-                                                                      ethyl                                                                         succinate                                                                     Aceto-   g      --    --    --    --     0.6                                  phenone                                                                       methyl                                                                        hydra-                                                                        zone                                                                          Aceto-   g       0.78 --    --    --     --                                   phenone                                                                       t-butyl                                                                       hydra-                                                                        zone                                                                          Tris-    g      --    0.6   0.6   0.3    --                                   (acetyl-                                                                      butyl-                                                                        hydra-                                                                        zonyl)-                                                                       benzene                                                                   2.  Degassing                                                                 a)    Without   2 × 4                                                                           1 × 4                                                                         2 × 5                                                                         --                                              hydrazone mins.   mins. mins.                                           b)    With      1 × 4                                                                           1 × 4                                                                         1 × 5                                                                         --                                              hydrazone mins.   mins. mins.                                           Properties of the composition (n.d. not determined)                           1.  Immediately after                                                             production                                                                a)    Cure time 40      55    35    26     30                                       (mins.)                                                                 b)    Tensile                                                                       shear                                                                         strength                                                                      (n/mm.sup.2)                                                                  Fe        5.1     14.3  7.6   n.d.   25.1                                     (ST1203)                                                                      PVC       4.7      3.2  3.7   n.d.    5.0                               2.  After 10 days                                                                 at 50° C.                                                          a)    Cure time 40      n.d.  35     0     37                                       (mins.)                                                                 b)    Tensile                                                                       shear                                                                         strength                                                                      (n/mm.sup.2)                                                                  Fe        4.4     n.d.  6.7   n.d.   17.2                                     (ST1203)                                                                      PVC       5.5     n.d.  4.7   n.d.    4.8                               3.  After 20 days                                                                 at 50° C.                                                          a)    Cure time n.d.    n.d.  35    n.d.   n.d.                                     (mins.)                                                                 b)    Tensile                                                                       shear                                                                         strength                                                                      (n/mm.sup.2)                                                                  Fe                      8.0                                                   (ST1203)                                                                      PVC                     4.0                                             4.  Stability in storage                                                      a)    at 80° C.                                                                        >2      >2    >2    0.0    n.d.                                     (h.)                                                                    b)    at room   >2      <2    n.d.  0.0    >2                                       temper-                                                                       ature                                                                         (months)                                                                ______________________________________                                         Footnotes .sup.a) to .sup.g) on the following page                            .sup.a) Mixture of methyl methacrylate and PLEXIDON M 449 in a ratio by       weight of 50:10. PLEXIDON M 449 is a high molecular weight polymethyl         methacrylate marketed by Rohm.                                                .sup.b) Mixture of methyl methacrylate and PLEXIGUM MB 319 in a ratio by      weight of 50:40. PLEXIGUM MB 319 is a methyl methacrylate/ethyl acrylate      copolymer marketed by Rohm.                                                   .sup.c) 10% iron(3) acetyl acetonate solution in hydroxypropylene             methacrylate                                                                  .sup.d) Hydroxyoctan4-one, C.sub.8 H.sub.16 O.sub.2                           .sup.e) 1.7% by weight iodine in tetrahydrofurfuryl methacrylate              .sup.f) Monomethacryloyloxyethyl phosphate                                    .sup.g) Methacryloyloxyethyl succinate                                   

Examples 1 to 3 clearly show the superiority of the compositionsaccording to the invention to the comparison composition according toU.S. Pat No. 4,855,379 in terms of controlled polymerization. Initially,they are stable in storage for a period of several months sufficient forpractical purposes and then readily cure in one hour on exposure to air,even at room temperature. The strengths obtained satisfy normalrequirements. No loss of activity is observed. By contrast, the knowncomposition begins to polymerize immediately after mixing of thecomponents, as stated in the US patent.

We claim:
 1. A composition comprising a radical-polymerizableolefinically unsaturated compound and a hydrazone corresponding to thefollowing general formula: ##STR3## in which n is a number of 1 to 3,R₁is hydrogen or an alkyl group containing up to 40 carbon atoms and R₂independently of the other substituents represents H or an aromatic oraliphatic group containing up to 40 carbon atoms,wherein saidcomposition is stable in storage.
 2. A composition as claimed in claim 1wherein said radical-polymerizable olefinically unsaturated compoundcomprises at least one member selected from the group consisting ofacrylic acid, methacrylic acid, acrylate compounds, methacrylatecompounds styrene, styrene derivatives and acrylonitrile, which memberscan be completely or partly present in the form of reactive preformedoligomeric or polymeric compounds.
 3. A composition as claimed in claim1 wherein said hydrazone is a 1,3,5-tris-(acetylalkylhydrazone)-benzene.4. A composition as claimed in claim 1 further comprising a stabilizeragainst radicals and oxygen.
 5. A composition as claimed in claim 4wherein said stabilizer is selected from the group of triphenylphosphine and iodide/iodine.
 6. A composition as claimed in claim 1further comprising a metal compound as an activator.
 7. A composition asclaimed in claim 6 wherein said metal compound is selected from thegroup of metal compounds derived from a member selected from the groupconsisting of Fe, Co, Mn, V.
 8. A composition as claimed in claim 1wherein said composition has a viscosity of at least 100 mPa.s.
 9. Acomposition as claimed in claim 1 wherein said composition has aviscosity of at least 300 mPa.s.
 10. A composition as claimed in claim 1wherein said composition has a viscosity of at least 500 mPa.s.
 11. Acomposition as claimed in claim 1 wherein said composition comprises atleast 20% by weight, based on the composition as a whole, of saidradical-polymerizable olefinically unsaturated compound and at least0.1% by weight, based on the composition as a whole, of said hydrazone.12. A composition as claimed in claim 1 wherein said compositioncomprises at least 40% by weight, based on the composition as a whole,of said radical-polymerizable olefinically unsaturated compound and atleast 0.5% to 7.5% by weight, based on the composition as ,a whole, ofsaid hydrazone.
 13. A composition as claimed in claim 1 wherein saidcomposition further comprises 0.01% to 5% by weight of a stabilizer. 14.A composition as claimed in claim 1 wherein said composition furthercomprises 0.01% to 1% by weight of, a stabilizer.
 15. A composition asclaimed in claim 1 wherein said composition further comprises 0.005% to5% by weight, based on the composition as a whole, of a metal compoundactivator.
 16. A composition as claimed in claim 1 wherein saidcomposition further comprises 0.005% to 1% by weight, based on thecomposition as a whole, of a metal compound activator.
 17. A compositionas claimed in claim 1 wherein said composition further comprises 0.1% to0.5% by weight, based on the composition as a whole, of a metal compoundactivator.
 18. A composition as claimed in claim 1 wherein saidcomposition further comprises 10% to 80% by weight of auxiliariesselected from the group consisting of fillers, pigments, thickeners,coupling agents and elasticizers.
 19. A composition as claimed in claim1 wherein said composition further comprises 10 to 50% by weight ofauxiliaries selected from the group consisting of fillers, pigments,thickeners, coupling agents and elasticizers.
 20. A composition asclaimed in claim 1 wherein said composition comprises in percentage byweight, based on the composition as a whole:(a) at least 40% by weightof the olefinically unsaturated compound; (b) from 1 to 4% by weight ofsaid hydrazone; (c) from 0.01 to 1% by weight of at least one stabilizerselected from the group consisting of triphenyl phosphine and iodine;and d from 0to 0.5% by weight of at least one metal activator compoundselected from the group of metal compounds derived from a memberselected from the group consisting of Fe, Co, Mn, and V.
 21. Acomposition of claim 20 wherein said hydrazone is a1,3,5-tris-acetylalkylhydrazone)-benzene.
 22. A composition of claim 20wherein said hydrazone is acetophenone methyl hydrazone.
 23. Acomposition as claimed in claim 1 further comprising a polymer, at leastpartly dissolved therein, to provide a viscosity above 500 mPa.s.
 24. Acomposition as claimed in claim 1 further comprising a polymer at leastpartly dissolved therein to provide a viscosity in the range from about3,000 to 10,000 mPa.s.
 25. A composition as claimed in claim 1 whereinsaid composition is stable in storage in the absence of light.
 26. Acomposition as claimed in claim 1 wherein said composition is stable instorage in the absence of UV light.
 27. A method for the production ofthe composition claimed in claim 1, said method comprising:degassing ahomogeneous mixture of the constituent components of said compositionwithout said hydrazone, heating said homogeneous mixture to roomtemperature, adding said hydrazone to said homogeneous mixture to form acomposition as claimed in claim 1, and degassing said composition asclaimed in claim
 1. 28. A method as claimed in claim 27 wherein saiddegassing of said homogeneous mixture without said hydrazone and saiddegassing of said composition are each performed by placing saidhomogeneous mixture without said hydrazone and said composition of claim1 under a vacuum of 0.5 torr for about 3 minutes at -196° C.